Pillar-shaped semiconductor device and method for producing the same

Abstract

In an SRAM cell circuit, an N+ layer 12a and a P+ layer 13a, which are present between first gate connection W layers 22a and 22b connecting to gate TiN layers 23a and 23b in plan view, which connect to the bottom portions of Si pillars 11a and 11b, and which extend in the horizontal direction, connect through a second gate connection W layer 29a to a first gate connection W layer 22c, which connects to the gate TiN layers 23a and 23b and extend in the horizontal direction. The second gate connection W layer 29a has a bottom portion within the first gate connection W layer 22c, and has an upper surface positioned lower than the upper surfaces of the gate TiN layers 23a to 23f and the first gate connection W layers 22a to 22d.

What is claimed is: 
     
       1. A pillar-shaped semiconductor device comprising:
 a first semiconductor pillar on a substrate and extending in a direction perpendicular to the substrate; 
 a first impurity region below the first semiconductor pillar; 
 a first impurity region connection layer connecting to the first impurity region, extending in a horizontal direction, and comprising a semiconductor or a conductor; 
 a second impurity region above the first semiconductor pillar; 
 a first gate insulating layer surrounding the first semiconductor pillar between the first impurity region and the second impurity region; 
 a first gate conductor layer surrounding the first gate insulating layer; 
 a second semiconductor pillar on the substrate and extending in the direction perpendicular to the substrate; 
 a third impurity region below the second semiconductor pillar; 
 a fourth impurity region above the second semiconductor pillar; 
 a second gate insulating layer surrounding the second semiconductor pillar between the third impurity region and the fourth impurity region; 
 a second gate conductor layer surrounding the second gate insulating layer; 
 a second gate connection conductor layer connecting to the second gate conductor layer, extending in a horizontal direction, and comprising a conductor; 
 a first contact hole connecting to the first impurity region connection layer and the second gate connection conductor layer, and having a portion overlapping, in plan view, at least the second gate connection conductor layer, the portion having a bottom portion positioned, in the perpendicular direction, lower than upper surfaces of the second gate conductor layer and the second gate connection conductor layer; and 
 a first connection conductor layer within the first contact hole and connecting to the first impurity region connection layer and the second gate connection conductor layer. 
 
     
     
       2. The pillar-shaped semiconductor device according to  claim 1 , wherein an upper surface of the first connection conductor layer, in the perpendicular direction, is lower than the upper surfaces of the second gate conductor layer and the second gate connection conductor layer. 
     
     
       3. The pillar-shaped semiconductor device according to  claim 1 , wherein the second gate conductor layer and the second gate connection conductor layer are layers of an identical material. 
     
     
       4. The pillar-shaped semiconductor device according to  claim 1 , wherein in plan view, the first contact hole includes:
 a second contact hole on the first impurity region connection layer or on the second gate connection conductor layer, and 
 a third contact hole that connects to the second gate connection conductor layer when the second contact hole is on the first impurity region connection layer, or that connects to the first impurity region connection layer when the second contact hole is on the second gate connection conductor layer, 
 the third contact hole has a bottom portion positioned lower than the upper surfaces of the second gate conductor layer and the second gate connection conductor layer, and 
 the first connection conductor layer includes the second connection conductor layer within the second contact hole and the third connection conductor layer connecting to the second connection conductor layer and being present within the third contact hole. 
 
     
     
       5. The pillar-shaped semiconductor device according to  claim 1 , further comprising:
 a first gate connection conductor layer connecting to the first gate conductor layer and extending in a horizontal direction; 
 a first interlayer insulating layer surrounding side surfaces of the first gate connection conductor layer and the second gate connection conductor layer; and 
 a second interlayer insulating layer surrounding a side surface of the first interlayer insulating layer, being formed of a material different from a material of the first interlayer insulating layer, and being used for formation of the first contact hole. 
 
     
     
       6. The pillar-shaped semiconductor device according to  claim 5 , further comprising:
 a third interlayer insulating layer between a side surface of the first gate connection conductor layer, a side surface of the second gate connection conductor layer, and a side surface of the first connection conductor layer, the third interlayer insulating layer having a dielectric constant smaller than a dielectric constant of a silicon oxide film. 
 
     
     
       7. The pillar-shaped semiconductor device according to  claim 5 , comprising:
 a fourth interlayer insulating layer having a pore between one or both of a side surface of the first gate connection conductor layer and a side surface of the second gate connection conductor layer, and a side surface of the first connection conductor layer. 
 
     
     
       8. The pillar-shaped semiconductor device according to  claim 4 , comprising:
 a fourth contact hole connecting to a bottom of the third contact hole and connecting to a material layer being positioned lower than the third contact hole and being a semiconductor or conductive layer; and 
 a fourth connection conductor layer within the fourth contact hole. 
 
     
     
       9. The pillar-shaped semiconductor device according to  claim 1 , wherein the first contact hole has a bottom portion within the first impurity region. 
     
     
       10. A method for producing a pillar-shaped semiconductor device including
 a first impurity region, a first semiconductor pillar, and a second impurity region disposed on a substrate in a hierarchical manner and in a direction perpendicular to the substrate; 
 a third impurity region, a second semiconductor pillar, and a fourth impurity region that are disposed on the substrate; in a hierarchical manner in the direction perpendicular to, the substrate, 
 the first impurity region below the first semiconductor pillar, 
 the third impurity region below the second semiconductor pillar; and 
 a first impurity region connection layer, formed of a semiconductor or a conductor, connecting to the first impurity region, and extending in a horizontal direction, 
 the method comprising:
 forming a first gate insulating layer so as to surround the first semiconductor pillar; 
 forming a second gate insulating layer so as to surround the second semiconductor pillar; 
 forming a first gate conductor layer so as to surround the first gate insulating layer; 
 forming a second gate conductor layer so as to surround the second gate insulating layer; 
 forming a second gate connection conductor layer connecting to the second gate conductor layer and extending in a horizontal direction; 
 forming a first contact hole connecting to the first impurity region connection layer and the second gate connection conductor layer, and, in plan view, having a portion overlapping at least the second gate connection conductor layer, the portion having a bottom portion positioned, in the perpendicular direction, lower than upper surfaces of the second gate conductor layer and the second gate connection conductor layer; and 
 forming a first connection conductor layer within the first contact hole so as to connect to the first impurity region connection layer and the second gate connection conductor layer. 
 
 
     
     
       11. The method for producing a pillar-shaped semiconductor device according to  claim 10 , wherein forming the first connection conductor layer comprises forming the layer so as to have an upper surface positioned lower than upper surfaces of the second gate conductor layer and the second gate connection conductor layer in the perpendicular direction. 
     
     
       12. The method for producing a pillar-shaped semiconductor device according to  claim 10 , wherein forming the second gate conductor layer and the second gate connection conductor layer comprises forming the layers of an identical material. 
     
     
       13. The method for producing a pillar-shaped semiconductor device according to  claim 10 , further comprising:
 forming a second contact hole on the first impurity region connection layer; 
 forming a second connection conductor layer within the second contact hole; 
 forming a third contact hole on and connecting to the second contact hole and the second gate connection conductor layer; and 
 forming a third connection conductor layer within the third contact hole, 
 the second contact hole and the third contact hole together forming the first contact hole, 
 the second connection conductor layer and the third connection conductor layer together forming the first connection conductor layer. 
 
     
     
       14. The method for producing a pillar-shaped semiconductor device according to  claim 10 , further comprising:
 forming a fourth contact hole on the second gate connection conductor layer; 
 forming a fourth connection conductor layer within the fourth contact hole; 
 forming a fifth contact hole on and connecting to the fourth contact hole and the first impurity region connection layer; and 
 forming a fifth connection conductor layer within the fifth contact hole, 
 the fourth contact hole and the fifth contact hole together forming the first contact hole, and 
 the fourth connection conductor layer and the fifth connection conductor layer together forming the first connection conductor layer. 
 
     
     
       15. The method for producing a pillar-shaped semiconductor device according to  claim 10 , further comprising:
 forming a first gate connection conductor layer connecting to the first gate conductor layer, and extending in a horizontal direction; 
 forming a first interlayer insulating layer surrounding side surfaces of the first gate connection conductor layer and the second gate connection conductor layer; and 
 forming a second interlayer insulating layer surrounding a side surface of the first interlayer insulating layer, formed of a material different from a material of the first interlayer insulating layer, and providing a higher etching rate than the first interlayer insulating layer with an etching species for forming the first contact hole. 
 
     
     
       16. The method for producing a pillar-shaped semiconductor device according to  claim 10 , further comprising forming a third interlayer insulating layer surrounding a side surface of the first connection conductor layer, and having a smaller relative dielectric constant than a silicon oxide film. 
     
     
       17. The method for producing a pillar-shaped semiconductor device according to  claim 10 , further comprising forming a fourth interlayer insulating layer surrounding the first connection conductor layer and having a pore therein. 
     
     
       18. The method for producing a pillar-shaped semiconductor device according to  claim 13 , further comprising:
 forming a sixth contact hole connecting to a bottom of the third contact hole, and connecting to a material layer being positioned lower than the third contact hole and being a semiconductor or conductive layer; and 
 forming a sixth connection conductor layer within the third contact hole and the sixth contact hole. 
 
     
     
       19. The method for producing a pillar-shaped semiconductor device according to  claim 14 , further comprising:
 forming a seventh contact hole connecting to a bottom of the fourth contact hole, and connecting to a material layer being positioned lower than the fourth contact hole and being a semiconductor or conductive layer; and 
 forming a seventh connection conductor layer within the fourth contact hole and the seventh contact hole. 
 
     
     
       20. The method for producing a pillar-shaped semiconductor device according to  claim 10 , wherein forming the first contact hole comprises forming the contact hole to have a bottom portion within the first impurity region connection layer.